Premium
Four A rabidopsis AREB / ABF transcription factors function predominantly in gene expression downstream of SnRK2 kinases in abscisic acid signalling in response to osmotic stress
Author(s) -
YOSHIDA TAKUYA,
FUJITA YASUNARI,
MARUYAMA KYONOSHIN,
MOGAMI JUNRO,
TODAKA DAISUKE,
SHINOZAKI KAZUO,
YAMAGUCHISHINOZAKI KAZUKO
Publication year - 2015
Publication title -
plant, cell and environment
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.646
H-Index - 200
eISSN - 1365-3040
pISSN - 0140-7791
DOI - 10.1111/pce.12351
Subject(s) - abscisic acid , transcription factor , biology , gene , mutant , arabidopsis , gene expression , transcription (linguistics) , microbiology and biotechnology , regulation of gene expression , osmotic shock , genetics , linguistics , philosophy
Under osmotic stress conditions such as drought and high salinity, the plant hormone abscisic acid ( ABA ) plays important roles in stress‐responsive gene expression mainly through three bZIP transcription factors, AREB1 / ABF2 , AREB2 / ABF4 and ABF3 , which are activated by SNF1 ‐related kinase 2s ( SnRK2s ) such as SRK2D / SnRK2 .2, SRK2E / SnRK2 .6 and SRK2I / SnRK2.3 ( SRK2D/E/I ). However, since the three AREB / ABFs are crucial, but not exclusive, for the SnRK2 ‐mediated gene expression, transcriptional pathways governed by SRK2D/E/I are not fully understood. Here, we show that a bZIP transcription factor, ABF1 , is a functional homolog of AREB1 , AREB2 and ABF3 in ABA ‐dependent gene expression in Arabidopsis . Despite lower expression levels of ABF1 than those of the three AREB / ABF s , the areb1 areb2 abf3 abf1 mutant plants displayed increased sensitivity to drought and decreased sensitivity to ABA in primary root growth compared with the areb1 areb2 abf3 mutant. Genome‐wide transcriptome analyses revealed that expression of downstream genes of SRK2D/E/I , which include many genes functioning in osmotic stress responses and tolerance such as transcription factors and LEA proteins, was mostly impaired in the quadruple mutant. Thus, these results indicate that the four AREB / ABFs are the predominant transcription factors downstream of SRK2D/E/I in ABA signalling in response to osmotic stress during vegetative growth.